Know Your Plants

Essential Questions To Answer While Designing Your Native Plant Garden

Knowing your plants intimately is essential for creating a successful garden design. This goes beyond basic information like height, spacing, and sunlight preferences found on plant tags. It involves understanding the specific habits and growth characteristics of each plant and how they interact with each other in a garden setting. It certainly takes more work upfront to gather this information but it will result in a much more successful design.

Is the Plant Native to My Area?

This is probably the most important question if you are a native plant gardener. Many resources exist to answer this question, but it will take some research. Here are some go-to resources:

• Ecozones: Find out what ecozone you live in and research what plants and ecosystems are found there. EPA Ecozones.

• BONAP: The Biota of North America Program provides detailed maps and information on plant distribution. BONAP

• The Gardener's Guide to Native Plants of the Southern Great Lakes Region: Everything you need to grow 150 species of native plants, including range maps for the Southern Great Lakes. Amazon Link

• VASCAN: A database of vascular plants in Canada. VASCAN

Is the Plant Suitable for My Garden?

As gardeners, we already know we have to consider soil type, drainage, sunlight, etc., when choosing plants. Native plant gardeners take it one step further and use the success of existing natural plant communities as a starting point for plant selection.

Natural plant communities show us that certain plants grow well together because they naturally coexist, while others do not. To benefit from the success of natural plant communities in our gardens, we must identify which plant community our garden most closely resembles, create a list of plants that naturally grow together in that community, and design our garden using only those plants. By choosing plants this way, you eliminate much of the guesswork about whether each plant will be compatible with others, thrive in your growing conditions, or look good together.

Most online resources will talk about what habitat or ecosystem a plant is found in. This is important information that you should be using in combination with sun, soil, moisture, etc., to determine a plants suitability to your site. Always make sure that the growing conditions in your garden resemble the natural habitat that the plant would typically grow in. A great way to do this is to get out into nature and pay attention to how the plants grow in their natural habitats.

What Are The Spreading Habits Of The Plant?

The spreading habit, or mannerism, of plants has a large impact on both the aesthetics and required maintenance of your design. If used in the wrong context, plants with prolific spreading habits (sometimes called aggressive) have the potential to send out runners or thousands of seeds and easily overwhelm a garden, leading to an incohesive and neglected aesthetic while creating a lot of weeding work for the gardener. Mannerism can be broken down into four general categories:

1. Clumping Habit/Rarely Self-Seeds: These plants generally stay in one spot and do not spread prolifically by seeds or rhizomes. They will expand their crown slowly each year. Self-seeding is possible in open/exposed soil, but seedlings are unlikely to take over a space. Examples include wild geranium, butterfly milkweed, white baneberry, wild ginger, and Culver's root.

2. Clumping Habit/Freely Self-Seeds: Some plants retain a clumping habit and stay in one spot but will freely self-seed in open soil. The best way to keep them in check is to plant your garden densely so the seedlings have no place to germinate. Examples include giant purple hyssop, nodding onion, red columbine, New England aster, and oxeye sunflower.

3. Spreading Habit/Rarely Self-Seeds: Plants will spread freely by rhizomes/runners but won’t self-seed prolifically, especially if bare soil is not present. These plants are generally good for groundcovers and filler species and generally don’t overwhelm plants that are taller than them. Examples include bush honeysuckle, field pussytoes, wild strawberry, oak sedge, and ostrich fern.

4. Prolific Spreading/Freely Self-Seeds: Plants will spread prolifically by seeds and/or rhizomes and can easily take over a new planting or even an established planting with gaps in its layers. These species may dominate a garden site within 2 or 3 years of establishment if not weeded out or used appropriately. For example, Canada goldenrod can easily dominate a site, especially in rich, loamy soil. Other examples include common milkweed and grass-leaf goldenrod (Euthamia graminifolia).

No matter which plant you choose, it's crucial to develop an intimate understanding of its traits and characteristics so you can use it appropriately in your specific context. This familiarity is acquired through trial, error, and extensive research. Get to know the spreading habitats of your plants by becoming familiar with the Grimes triangle. It can help you anticipate how plants will behave in your garden and how they will react in different environments and interact with other plants. Grime's Triangle

How May Site Conditions Affect Growing Habits of the plant?

• Plants behave differently in different growing conditions. For example, Canada anemone is a very prolific spreader in sunny, moist, rich soils. Plant it in dry shade, and it is very well-mannered.

• Some plants will self-seed prolifically in bare/exposed soil. However, in a densely planted garden, they won’t self-seed nearly as much because their seeds don’t have as much bare/exposed soil to germinate in. Good examples of this are Golden Alexanders or Black Eyed Susan.

• Plants become floppy when planted in too much shade, excessively rich soil, or when not given enough root competition. For example, foxglove beardtongue is known to flop in gardens because it can become tall and heavy with blooms. Compare this to a wild specimen that doesn’t have the resources to sprawl (due to surrounding plant competition), and you will see two very different growth habits from the same plant.

Lifecycle: Is the plant short or Long-Lived?

• Plant lifecycles can be divided into annuals, biennials, short-lived perennials, or long-lived perennials. Annuals and biennials should be dotted around a site rather than planted in large clumps otherwise they will leave behind gaps at the end of their short lifecycles. Longer-lived plants should be the backbone of your plantings as they have a more permanent presence in the landscape.

• Some plant’s lifespans change according to growing conditions. For instance, hairy beardtongue and hoary vervain both live a shorter life when planted in rich soil as they naturally grow in poor, dry soil.

• Some plants behave differently depending on when their seeds were started. For example, American bellflower acts like and annual if its seeds are sown in the fall but acts like a biannual if its seeds are sown in the spring.

Is It A Warm Season or Cool Season Grower?

• You may have noticed that not all plants pop up from the ground at the same time in the spring. Some green up before the snow has finished melting while some don’t pop up until later in the spring. Butterfly milkweed is a great example. Often times, gardeners think their plant has died but it just really likes to wait for warmer weather before it pokes its head out of the ground. This is an important growth trait to consider becuase it means that we should pair butterfly milkweed with a plant that can start growing early before it does.

• Warm and Cool season considerations are especially important when using native grasses. For design purposes, let’s divide native grasses into two categories:

  • Cool Season grasses are those that grow most actively during the cool weather of spring and fall, and go dormant in hot weather. The best time to plant, or sow seeds of, cool season grasses is in spring or fall. Bottlebrush grass and Junegrass are examples of cool season grasses.

  • Warm season grasses grow most actively during warm weather from late spring to late summer. They stay lush and green during the hot, dry weather of summer (right about the same time as your lawn is taking on that ugly, brown look). The best time to plant, or sow seeds of, warm season grasses is in late spring/early summer as the soil temperatures start to warm up. Most prairie species are warm-season including Little Bluestem and Indian Grass.

• Some plants are evergreen or semi-evergreen and provide extended greenery in the garden. These are ideal to include in the garden not only for aesthetics but for erosion control and wildlife value too. Sedges are great cool-season growers and provide greenery for much of the year. Why your garden needs sedges.

How Will the Plant Look When Not in Bloom, Especially During the Winter?

Plants are only in bloom for a relatively short period of their entire lifecycles. Not considering how they look the rest of the time is a big mistake.

• Plants are not meant to grow as individual specimens. When planted as individuals, they can look less attractive than what the gardener originally envisioned. For example, many asters look scruffy around their base later in the season because they naturally lose their lower leaves. This is because, in the wild, they normally grow surrounded by companions, such as grasses, that hide their scraggly base. For this reason, New England Aster should be planted with companions that can hide its base.

• Spring ephemerals go dormant by early to mid-summer, so they need suitable partners to fill in the gaps, such as sedges, grasses, or later-blooming perennials.

• Don’t forget about the winter! Choose long-lived plants with sturdy stems for reliable winter interest. Combine multiple shapes of seed heads. Native grasses have wonderful four-season interest. Some plants look great all year but are not visually noticeable over the winter. Learn how to design for winter interest.

• Does the foliage have attractive fall colors? Many plants will produce attractive fall foliage that rivals the fiery hues of the trees above them. Great examples include foxglove beardtongue, wild geranium, and bush honeysuckle.

What Pot Size Do I Choose?

The size of potted plants is often not given much consideration but it’s not a one-pot-size-fits-all type of deal. The size of potted plant you choose at planting time is dependent on budget, time-restraints, site conditions and growth habits of the plant.

• Generally, smaller potted plants establish faster and don’t require as much water during the establishment phase. They are also much faster to plant and can cover a much larger area with a smaller budget.

• Groundcover plants should be planted in small plugs so they can be economically planted en masse as a mulch replacement.

• Some species take a few years to establish or reach mature size. Plant these in larger pots to give them a head start.

• Don’t bother planting annuals or biennials in large pots as they will only live for a couple years.

• Planting large potted plants under large trees can lead to frustration with roots and extended planting times. Choose small potted plants when planting around roots or even just in rocky, hard-to-dig-in ground.

How can you compile all this information into a cohesive plant list?

Answering these questions adds a layer of complexity to plant selection and natural garden design. However, the extra effort is well worth it, resulting in a more successful design and better plant choices. This knowledge comes from experience, research, and working closely with plants over many years.

If you want to benefit from years of knowledge and experience, reach out to us at In Our Nature. Since 2018, our mission has been to empower homeowners and businesses to create meaningful connections with nature through natural garden design. Our gardens are designed to be beautiful, restore native biodiversity, and create a more rewarding experience for you, the gardener.

Discover how we can help get your project started on the right track: